A novel approach to vaccination against cancer is to exploit dendritic cells (DCs) as "nature's adjuvants" and actively immunize cancer patients with a sample of their own DCs primed with tumor antigens. DC vaccination is, however, still at an early stage, slowed in part by the need to carry out research in humans. Nevertheless, valuable proofs of concept have been obtained with respect to the capacity of DCs to expand cancer-directed immune responses. The methods for preparing DCs are being improved continuously, and there are many opportunities to improve efficacy at the level of DC biology. An increased number of Phase I, II and III studies will drive this new area of human research.